Creating an object out of other objects
1) Duplifaces (or dupliverts)

After creating the object to duplicate (hexagon in this case) and parented it to the armored suit, you should enable in the parent's Duplication panel (in the Object tab) the option Faces.



By enabling the Scale option, the hexagon will be scaled accordly to the face's size, so in the part of the mesh where the quads are more dense, you'll have more dense hexagons too.

Till you don't Make duplicates real, the hexagons will be attacchet to the mesh. This can be really helpful in animating meshes with shape keys, or transfer cloth simulation from the parent to the child without involving all the duplicated geometry.



Note: that you can study the hexagon pattern in a way that can cover the whole suit without leaving spaces, in order to completely replace the base mesh, but a more suitable way to do this is:...

2) Tissue add-on

As stated by the creator:


  Tessellate tool allows the user to copy a selected object (Component) on the faces of the active object (Generator), adapting its bounding box to the shape of quad-faces.


There are a few option that can help you in the modeling, such as automatically vertex merging, proportional Z-scale. I think that is currently the best option to repeat a pattern on a surface while adapting the geometry to the face scale and get an organic look. 





I was in hurry and I didn't used hexagons but octagons because the pattern was easier, but I'm sure that with some time you can get the effect you want.

The add on is currently in develop, so it still doesn't support shape keys, uv,... but they are working on.

Here's the blender artist thread about it.



The add-on include also another feature, called "Dual mesh" that:


  ... modify the selected meshes creating dual meshes. Dual Mesh output is a polygonal mesh derived from the triangular mesh. Quadrangolar meshes are automatically converted to triangular before.


Balsically youll'get a pattern of hexagonal N-gons from every mesh, which you can extrude.

Triangulate your mesh, that simply run the command and you'll get:



Than you can extrude individual faces to get an invincible-dragon-scale armor:



Credits:
Armor suite model from blendswap made by simitron